[TenTec] Just replaced the backlight on my T-T Delta II

Sun May 8 23:47:43 EDT 2016

The Argonaut II and Delta II use an electroluminescent strip for the LCD 
backlight.  I bought several of them from Britain.  I have also found 
that the oscillator circuit that drives the transformer to provide the 
power for the strip can stop oscillating.  Probing around the two 
transistors that form the circuit with my digital multimeter was often 
effective in getting it going again.  I think that the lifespan of these 
strips should be pretty long.  GE used to make night lights out of them.

Your mileage may vary.

Steve WA9JML

On 5/8/2016 8:57 PM, Gary J FollettDukes HiFi wrote:
> I have replaced an Orion illuminator and half a dozen Icom 756 xxx illuminators with excellent results using LED’s from LCD Parts.
>
> They sell drivers if your radio’s controller is not compatible with a particular lamp that you want to use.
>
> Ten Tec uses the LED’s in triads in series, and a few triads in parallel. That makes the allowable drive voltage about 3.7 volts. This is pulse width modulated to hold the brightness (and heat) down.
>
> The LCD Parts LED’S are all in series, thus requiring ~13.8 volts drive, also pulse width modulated.
>
> I did manage to do my last install and preserve some degree of brightness adjustment using the original brightness control on my last Pro 3 and am certain this would work on the Orion as well.
>
> However, Ten Tec did not make the illuminator brightness a consumer adjustment in the Orion (I do not know why) and I cannot even find it in the service manual. I am assuming they set the PWM duration to the level they thought gave good illumination, reasonable heat and good  lifetime.
>
> I guess 14 years would be defined as good lifetime…
>
> Ten Tec were was ahead of everyone else at the time with their LED illuminators as all of the competition then used CFL’s, which stink, have always stunk and always will stink. Short lifetime, ugly color rendition, slow achievement of equilibrium, toxic material in large quantities, very fragile, require very high voltage. YUK! I won’t even use them for household illumination any more.
>
> Gary
> W0DVN
>
>
>> On May 8, 2016, at 8:42 PM, <km2km at twc.com> <km2km at twc.com> wrote:
>>
>> Carl,  I did not have any problems with the decimals or any other feature of the screen.
>>
>> Joe, K8MP,  TNX for the comment -
>>
>> I wonder just how many hours these back lights last?
>>
>> 73 all,
>>
>> Kris KM2KM
>> MERSCHROD
>> 123 Warren Road
>> Ithaca, NY 14850
>>
>> ---- Carl Winkles <jcwinks at att.net> wrote:
>>
>> =============
>> Hi Kris. The last time I replaced the backlight in a Delta II the rig wound up with an extra dot in the display. Ten Tec said it was caused by stray capacitance. I am just curious if you had the same issue?
>> CarlK4SEV
>>
>>     On Sunday, May 8, 2016 10:04 AM, "km2km at twc.com" <km2km at twc.com> wrote:
>>
>>
>> Just a quick note, For what it is worth
>>
>> I had bought this replacement from England a few years ago and only now got to it - sorry I do not have the name of the company.  The backlight strip came with wires and a plug.
>>
>> The replacement is delicate, but not a struggle:
>>
>> Remove top and bottom covers.
>>
>> Loosen the top two screws on the side of the front panel,
>>
>> Gently tilt the front panel forward;
>>
>> Unplug three plugs that are on the screen - there are two plugs on the right side, and one plug (serving the back light) on the left of the screen. (Make note of which is which - but it is really straight forward)
>>
>> Unscrew the screen - four screws.
>>
>> lift off the screen by gently pressing from the front - might be a snug fit.
>>
>> The backlight is plastic and slips between the glass screen and the intelboard and is fed by two wires that wrap around the board from the two prongs frowm which one of the plugs was pulled.
>>
>> snip the two wires (really are like thick traces of flat wire) as close to the backlight strip as possible.
>> Gently fold back the two traces so that they are out of the way of the backlight strip as you slide it out.
>>
>> I used needle-nosed pliers to pull the backlight strip out.
>>
>> The replacement back light had two wires and a plug long enough the replace the wires in the harness and not use the plug and folded back wires on the board.  I chose to snip them off leaving just enough wire to solder to the folded back traces.  I used tape to hold the traces and wires to the board.
>>
>> In retrospect, the alternative, use the plug and all, is probably the better idea in retrospect, but the plug needs to be whittled a bit to fit. That would save snipping the wires, pealing the insulation and soldering.
>>
>> It is an easy repair and it is so nice to see the screen without having to shine a bright light on it!
>>
>> 73
>>
>>
>>
>> Kris KM2KM
>> MERSCHROD
>> 123 Warren Road
>> Ithaca, NY 14850
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